1. Field of the Invention
This invention relates in general to magnetic heads, and in particular to a magnetic head -- and to a method for making such a head -- in which the windowed back section of the head is bridged by a single domain thin magnetic film coated wire having a sense coil wound thereabout.
2. Description of the Prior Art
In practicing the teachings of McClure (U.S. Ser. No. 835,110) and Moeller (U.S. Ser. No. 835,105), commonly assigned, it happens that anomalies may appear in the characteristic curves of some, but not all, of the magnetic heads according to those teachings. For example, at a certain current through the sense coil of a head according to the teaching of Moeller . . . the current serving to apply a bias field along the hard axis of the film . . . a "switching" transient appeared in the output of the sense coil. As will appear below, the invention postulates a theory to explain such behavior and provides apparatus/method, in correspondence with such theory, to preclude such behavior.
It turns out that thin film wire sensors are supplied by their suppliers in throw-away glass shipping tubes, such tubes serving to protect the fragile thin (about 3 microns or less) magnetic films from handling damage. Such glass shipping tubes are, in one aspect of the invention, modified and reused to implement the theory which is at the root of the invention.